SEEDS TRANSPORTED BY WIND. 
53 
But in many instances a strong breeze, sometimes a 
whirlwind, has been seen to carry these mature fruits 
from the tree to a distance of thirty rods. 
A thin sheet of paper descends more slowly than the 
same material put in the form of a ball. On the same 
principle, many seeds and fruits are flattened, 
apparently for a purpose ; not that they may 
be easily shot through the air by some elastic 
force, not to increase their chances for attach- 
ment to animals, but to enable the wind to 
sustain them the longer and carry them farther. 
Some seeds and dry fruits are said to have 
wings, with the general understanding that 
they are by this means better fitted 
to be sustained in air. We shall 
Fig. 41. — Sin- 
find that all or nearly all flattened gle fruit of 
i -a -• « . silver maple. 
seeds and dry iruits, also winged 
seeds and fruits, are one-sided, unbalanced, 
and more or less twisted ; consequently, in 
falling to the ground they whirl about, and 
are thus kept much longer in the air than 
they would be if shaped more like a winged 
arrow. Even the wings on the fruit of some 
of the ashes are twisted, though many of them 
are flat. Experiments with these things are 
sure to interest inquisitive children, or even 
older persons, when once started right ; they 
are likely to prove as interesting as flying kites, skating, 
Fig. 42. 
Winged seed of 
pine. Want of 
symmetry 
causes it to 
whirl about 
while falling. 
